Coaxial spark gap



March 2, 1948. E. -M. WILER COAXIAL 'SPARK GAP Filed Aug. 17, 1945 FIG.2.

IN V EN TOR.

EDWARD M. WILER ATTORNEY Patented Mar. 2, 1948 UNITED STATES @FFICE AX A S RK G Edward M. Wiler, Belmar, N. J,, assignor to the United States of America, as represente 33' the Secr t :o War Application Augustll, 1943, Serial No. 498,976

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) 6 Claims.

erally improve spark gaps, and more particularly open air spark gaps for pulse modulation. In accordance with the present invention, the gap co si s Q a me alroa passing t rou h a d posed coaxially in an open-ended-metaltube, said rod and tube being made of high temperature m tal. The spark iump iias ell acr the gap between the outside of therod and the inside of the tube.

To accomplish the foregoing general object, and

such other more detailed objects as will hereinafter appear, my invention resides in-the spark gap elements and their relation one to the other as hereinafter are more particularly described in the specification and sought to be defined in the claims. The specification is accompanied by a drawing in which Figure 1 is a vertical section taken longitudinally through the structure of a spark gap embodying the present invention, with the lower screws shown (according to conventional mechanical drafting practice) in the same plane as the upper screws for clarity; and

Figure 2 is a transverse section taken approximately in the plane of the line 22 of Figure 1, wherein the screws are shown in their actual relative positions.

Referring to the drawing, the electrodes of the spark gap are the rod l2 and the open-ended tube Id. The tube 14 is preferably used as the cathode or consumed electrode, because it is of larger area. It is received in a. support, specifically an insulation disk l6, which in turn is fitted into an insulation cylinder Ill. The tube I4 is locked in position, as by means of a long set screw 20, which acts also to provide an external electrical connection, as by means of a lead 22 received between two nuts on screw 20.

The rod I2 is longer than tube 14, and is sup ported at both ends, outside the ends of the tube. In the presentcase each end of the rod is supported by three radially disposed screws 24, threadedly received in the insulation tube H3. The adjustment of these screws may be locked by appropriate lock nuts 25. By properly adjusting the screws, the rod I2 may be centered accurately in tube l4. Relatively light tension springs 25 may be provided to hold the rod in position during adjustment of the screws. Electrical connection to the anode may be made at one of the screws, as for example by means of a lead -28 held betweentwo nuts, received in-this case on the upper rig-ht hand screw.

ln the particular case illustrated, the anode i2 is made of tungsten, and the cathode i4 :is made of tantalum, but other hightemperature metals may be used. No difiiculty arises with sputtering or cobweb-like formation of metalbetween the electrodes. These-form in asealedenvelepe of inert gas, but do not form inopenair.

The" insulation tube 18 is preferably made of l\ iycalex or equivalent insulation.

The spacing of the electrodes has been exaggerated in the drawing for the sake ofclarity,

and in practice the diaineter of the tube M, relative to the diameter of the anode rod 42, may be made much smaller than indicated in the present drawing. I

While air cooling is not essential, it may be provided very conveniently with the present tubular structure, because an air stream may be blown into one end of tube in and will then flow longitudinally through the tube 5 t.

It is believed that the construction and opera tion of my improved spark gap, as Well as the advantages thereof, will be apparent from the foregoing description. The electrodes have large surface area, thereby prolonging the operating life of the gap. While an air blast is not essential, the structure of the gap makes it ideally suited for use with an air blast, should special circumstances make it necessary, either for extinguishing the spark, or for cooling the electrodes.

It will be apparent that While I have shown and described my invention in a preferred form, changes and modifications'may be made in the particular structure disclosed without departing from the spirit of the invention as sought to be defined in the following claims.

I claim:

1. A spark gap comprising a rod and an open ended tube, said rod being disposed coaxially within said tube, and passing all the way through the same so as to extend beyond said tube at both ends thereof, and means to support said rod relative to said tube at points along said rod beyond the ends of said tube so as not to interfere with the flow of a cooling medium flowing longitudinally through said tube.

2. A spark gap comprising a rod and an open ended tube, said rod being disposed coaxially within said tube, means to support said rod at points beyond the ends of said tube, said rod and tube being made of high temperature metal, and separate electrical connections to the rod and tube, the arrangement being such that when the gap breaks down a spark jumps radially from the rod to the tube.

3. A spark gap comprising a metal tube, a metal rod coaxially disposed in said tube, said rod being longer than said tube and projecting therefrom at both ends, an insulation tube substantially larger in diameter than the metal tube surrounding said metal tube, means in said insulation tube receiving and supporting said metal tube, and supports near the ends of the rod beyond the ends of the metal tube, said supports extending between said insulation tube and said rod.

4. A spark gap comprising a metal tube, a metal rod coaxially disposed in said tube, said rod being longer than said tube and projecting therefrom at both ends, an insulation tube substantially larger in diameter than the metal tube surrounding said metal tube, means in said insulation tube receiving and supporting said metal tube, and at least three radially-disposed, adjustable support screws bearing against the rod near its ends and beyond the ends of the metal tube, said screws passing through said insulation tube and being radially adjustable to center the rod within the metal tube.

5. A spark gap comprising a tube made of high temperature metal, a rod made of high temperature metal and coaxially disposed in said tube, said rod being longer than said tube and projecting therefrom at both ends, an insulation tube substantially larger in diameter than the metal tube surrounding said metal tube, said insulation tube being substantially longer than the metal tube and having the same order of length as the rod, means including an insulation disk Within said insulation tube and receiving and supporting said metal tube, a relatively long set screw bearing against said metal tube and forming a connection terminal therefor, and at least three radially-disposed, adjustable support screws bearing against the rod near its ends and beyond the ends of the metal tube, said screws passing through said insulation tube and being radially adjustable to center the rod within the metal tube.

6. A spark gap comprising a metal tube, a metal rod coaxially disposed in said tube, said rod being longer than said tube and projecting therefrom at both ends, an insulation tube substantially larger in diameter than the metal tube surrounding said metal tube, means in said insulation tube receiving and supporting said metal tube, at least three radially-disposed, adjustable support screws bearing against each end of the rod beyond the ends of the metal tube, said screws passing through said insulation tube and being radially adjustable to center the rod within the metal tube, and relatively light pull springs extending from the ends of said rod to the insulation tube in order to help hold the rod in position during adjustment of the adjustable support screws.

EDWARD M. WILER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 745,114 Nicholas Nov. 24, 1903 1,101,728 Craft June 30, 1914 1,132,589 Kroger Mar. 23, 1915 1,256,270 Seibt Feb. 12, 1913 

